Date of Award:

5-1970

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Wildland Resources

Committee Chair(s)

Frederic H. Wagner

Committee

Frederic H. Wagner

Committee

Lewis Nelson Jr.

Committee

David F. Balph

Committee

William T. Helm

Committee

George H. Kelker

Abstract

The annual demography of a population of antelope ground squirrels in Curlew Valley, Utah was studied by measuring population density, natality, and mortality. Capture- recapture techniques yielded lower estimates than the Hayne strip- census. The estimates suggested 1968 was a year of population decline.

One hundred seventy- three squirrels were collected and autopsied to obtain sex ratio, age structure, natality, and mortality data. The seasonal sex ratios for adult and yearling squirrels showed 82 percent females in spring 1968, this gradually changed to 56 percent by winter. The seasonal sex ratios of the young squirrels showed 59 percent females upon emergence from natal burrows in summer 1968, increasing to 79 percent by winter.

The squirrels collected were aged by cementum annuli. The oldest were believed to be 5 years old. They composed 1.2 percent of the collection while young- of- the-year composed 38. 7 percent.

The estimate of mean corpora lutea was 7.6, the mean embryo count was 7.2, and the mean post-partum placental scar count was 5.8. The mean corpora lutea count for yearlings was statistically lower than the count for adults and the mean ovulation rate for 1968 statistically lower than the rate for 1969. An estimate of litter size from four nests gave a mean of 4.5. In 1968, the conception rate was 91 percent with yearlings comprising 75 percent of those not conceiving. In 1969, the rate was 100 percent.

Pre-Emergence mortality of the young was 41 percent. post-emergence mortality was 86 percent, and mortality, March-November, 1968 was 92 percent.

Adult and yearling spring-to-spring mortality for study area squirrels calculated from retrap data was 81 percent. Spring-to-spring mortality calculated from age distribution data and Ricker's formula was 71 percent. The spring-to-fall mortality for 1968 calculated from density estimates and age distribution data was 53 percent.

Checksum

686029f797843b767ad2ecd9e88bced0

Download

Included in

Life Sciences Commons

Share

COinS

Copyright for this work is retained by the student. If you have any questions regarding the inclusion of this work in the Digital Commons, please email us at .